Use of fluids in drilling, completion and workover operations in oil and gas wells results in substantial loss of potentially recoverable petroleum materials. During finishing operations in the completion of a well, a variety of water containing fluids may be used, including drill in and completion fluids and the like, that often also include brine. In the course of these operations involving water containing fluids permanent damage to the production formation is caused by introduction of water into the formation that decreases and often irreparably damages the formation and reduces the amount of oil and/or gas that may be recovered from the producing formation. Increased water saturation in the producing formation that decreases the permeability to oil and gas therein can be a significant factor in this damage.
The industry has devoted much effort to off-setting the damage done to formations after completion of the well and subsequent production as in secondary recovery and well stimulation operations. Little effort, however, has gone into minimizing formation damage during drilling, workover and completion operations. It is much more desirable to attempt to minimize formation damage during finishing operations in completing a well and to reduce the presence of interstitial water in the production formations than at some later time.
It is therefore, an object of this invention to provide means to prevent or minimize formation damage and subsequent loss of potential oil and gas production because of invasion of aqueous fluids from a wellbore into production zones. It is desirable to provide an additive for such fluids to minimize formation damage from loss of drilling, workover, completion or stimulating fluids into a petroleum reservoir, to reduce interfacial tension to minimize water blocked formations. The additives should be compatible with formation fluids, promote water wetting and demulsification, have good thermal stability and be effective over a wide range of brine concentrations.